The present invention relates generally to thermoset polymeric compositions useful in structural applications, and more particularly to turbine blades comprised of two or more components made from different materials, one of which is the thermoset polymeric compositions of the invention.
Turbines include, but are not limited to, gas and steam turbine power generation equipment and gas turbine aircraft engines. A gas turbine includes a core engine having a high pressure compressor to compress the air flow entering the core engine, a combustor in which a mixture of fuel and compressed air is burned to generate a propulsive gas flow, and a high pressure turbine which is rotated by the propulsive gas flow and which is connected by a larger diameter shaft to drive the high pressure compressor. A typical front fan gas turbine engine adds a low-pressure turbine (located aft of the high pressure turbine) which is connected by a smaller diameter coaxial shaft to drive the front fan (located forward of the high pressure compressor). The low-pressure compressor is sometimes called a booster compressor or simply a booster.
The fan and the high and low pressure compressor and turbine engines have turbine blades each including an airfoil portion attached to a shank or dovetail portion. Rotor blades are those turbine blades each including an airfoil portion attached to a shank or dovetail portion. Stator vanes are those turbine blades which are attached to a non-rotating turbine stator casing. Typically, there are alternating circumferential rows of radially-outwardly extending rotor blades and radially-inwardly extending stator vanes. When present, a first and/or last row of stator vanes (also called inlet and outlet guide vanes) may have their radially inward ends also attached to a non-rotating gas turbine stator casing. Counter rotating “stator” vanes are also known. Conventional gas turbine blade designs typically have airfoil portions that are made entirely of metal, such as titanium, or are made entirely of continuous fiber reinforced composites (CFRC). The all-metal blades are heavier in weight which results in lower fuel performance and requires sturdier blade attachments, while the lighter all-composite blades are more susceptible to damage from bird ingestion events. Known hybrid blades include a composite blade having an airfoil shape which is covered by a surface cladding (with only the blade tip and the leading and trailing edge portions of the surface cladding comprising a metal) for erosion and foreign object impacts. The fan blades typically are the largest (and therefore the heaviest) blades in a gas turbine aircraft engine, and the front fan blades are usually the first to be impacted by foreign objects such as birds. What is needed is a lighter-weight gas turbine blade, and especially an aircraft-engine gas turbine fan blade, which is both lighter in weight and better resistant to damage from ingestion of foreign objects and blade out events.